By: Bonnie L. Grant, Certified Urban Agriculturist
Verbena seed germination times depend upon the variety, so don’t get discouraged. The seeds need well-draining soil in a good, sterile starting medium, light moisture and total darkness.
Overall, growing verbena from seed is easy and can save you money on your annuals.
Planning on the right time to sow seeds can make all the difference in the world between success and failure. If you plant too early, seedlings may die in overly wet or cold weather. If you plant too late, you may not get flowers before the growing season ends.
Verbena is cold tender and seedlings are even more prone to cold sensitivity. You may sow verbena seeds indoors 10 to 12 weeks before planting them out or wait until spring and plant them in a cold frame or raised bed. Just make sure there is no chance of frost. The actual month will vary, dependent upon your USDA zone.
Verbena seed germination can take as little as 20 days or up to a month or more and, in most cases, requires cold stratification in order to be successful. The seeds are variable, so be patient.
Use a well-draining, moist potting mix if starting seed indoors. Sow verbena seeds in compartmented flats. Place a few seeds in each compartment and thin them after germination. Verbena seed germination requires darkness. You can simply dust some soil over the seeds or cover the flat with black plastic.
In outdoor settings, wait until no freezes are expected and prepare a garden bed. Incorporate compost or other organic matter and rake the bed to remove any impediments, such as rocks or twigs. Sow seeds just as you would indoor plants.
Once germination takes place, remove black plastic if applicable. Wait until the first set of true leaves appears and then thin plants to 12 inches (30 cm.) or one plant per compartment.
Harden off plants by giving them gradually longer exposure to outside conditions for a week. Once plants are used to the wind, light and other conditions, it is time to transplant them.
Transplant outside when temperatures have warmed and soil is workable. Space plants 12 inches (30 cm.) apart in full sun. Keep competitive weeds away from seedlings and keep the soil moderately moist.
Pinch plants back after a month to promote thicker, denser verbena. Deadhead regularly once plants begin to bloom to encourage more flowers. At the end of the season, save more seed to continue the easy beauty of verbena.
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Grow Verbena bonariensis from seed, for months of prairie-style, tall flowers that butterflies adore.
Published: Friday, 8 March, 2019 at 1:12 pm
Verbena bonariensis flowers on tall, wiry stems and can be planted with a variety of different perennials, including grasses. It has a long flowering season, making it an ideal plant for low-maintenance gardens and herbaceous borders.
Verbena bonariensis works well in a number of garden settings, such as cottage and contemporary gardens, due to its height and airy appearance. It’s also beneficial for attracting wildlife, particularly butterflies.
Growing tall on strong, wiry stems, Verbena bonariensis can be planted in with a variety of different plants. It works particularly well when used in prairie-style planting, in conjunction with other prairie plants such as rudbeckia and ornamental grasses.
Seeds can be sown directly in the ground in spring, or you can start them off under glass in late-winter, and plant them outside later. For best results grow Verbena bonariensis in full sun to partial shade, in moist but well-drained soil. Incorporate plenty of organic matter into the soil before planting out and mulch plants annually with well-rotted compost or manure.
Verbena bonariensis isn’t fully hardy, so plants may be damaged by winter frosts. Protect the roots with a layer of straw or mulch in winter, and don’t cut back the dead stalks until new ones have emerged in spring. If left, Verbena bonariensis will self-seed freely and naturalise in borders, so any plants lost to frost should be replaced by their offspring.
Verbena bonariensis is a fantastic late source of nectar for butterflies. Grow it in large swathes to lure them in!
Verbena bonariensis plants are tall upright plants with a woody base that can reach heights from 24 to 72 inches (60–200 cm), more commonly they are about 48–60 inches (120–150 cm), and have a spread of 16 to 36 inches (40–90 cm).
Green oblong or ovate-lanceolate leaves are present from spring to fall/autumn. These are toothed and typically reach about four inches in length (10 cm) with a width of three inches (7.5 cm).
Plants bloom from June to October with fragrant violet/lavender flowers. These are small, tightly clustered, and present at the ends of both axillary and terminal stems.
Verbena is a must-have plant for every garden because of its tendency to bloom from spring to fall with very little maintenance. Although verbena is considered to be perennial in warm climates where frost is never a danger, it has to be grown as an annual in climates that have freezing temperatures.
Verbena plants grow in clumps six to 10 inches tall, making it ideal as a hanging basket plant. The colorful blooms can be red, white, pink, mauve, purple or apricot and provide pretty accents for rock gardens, window boxes or borders.
Verbena can be started from seeds, but it does take them a long time to germinate. Start indoors in late winter by placing two seeds in peat or fiber pots. Cover very lightly with soil. Water taking care not to make the soil too wet and be prepared to wait about a month for the seeds to show any signs of life. Once the plants have three or four leaves, they can be hardened for outdoor use.
Verbena is a common plant that grows well in U.S. Department of Agriculture hardiness zones two through eight, so most garden centers will carry plants. Plant verbena in full sun in areas of the garden or yard that have good drainage. The plants, which should be spaced 10 to 12 inches apart, require eight to 10 hours of sunlight a day and they do not like soil that is on the dry side.
You can also take cuttings of verbena to start additional plants. Some folks dig up verbena plants in the fall and keep them indoors for the purpose of establishing growth for cuttings.
Verbena plants do not require a lot of attention. Once established, water the plants only when they dry out. Fertilize once in the spring of the year after they have been planted and established outdoors. Deadhead the faded blooms so that blooming continues long into the gardening season.
If you live in an area where verbena grows as a perennial, cut the plant back in the fall. If verbena is an annual in your area, remove the plants after they finish flowering in the fall.
There are not many pests that impact the growth of verbena, but aphids, spider mites, thrips, slugs and snails can take their toll. A spray of soap diluted with water can be effective in the battle of the bugs. Slugs can be defeated by setting an aluminum pie plate filled with beer (use a cheap variety) out in heavily infested areas of your yard or garden. The slugs will be attracted to the beer and will die after taking their fill of the intoxicating beverage.
Diseases such as powdery mildew and leaf spot can affect the plants. There are natural and chemical products available to help control these problems. Ask for advice at your favorite garden center.
Here’s a great site with more information on growing verbena.
And, don’t miss this fact sheet on verbena.
Maria Iles says
Do you leave the plate under the pot when watering Verbena pls?
how soon can they be planted out? After any danger of frost ?
Can seeds be started in June or is it to late
The fastest-growing plants and the most abundant flowers are achieved when "Imagination" is planted in full sun. It will grow in a wide variety of soils, from sand to clay, with pH ranging from the acidic to the alkaline. Seeds are best planted outdoors any month of the year except January in USDA zone 10. Gardeners in USDA zone 9 should plant them 10 weeks before the expected last date of frost. The ideal germination temperature is from 65 to 75 degrees Fahrenheit. If they are grown as perennials in a frost-free area, they will last two to three years.
Seeds are best planted in a mixture of equal parts fine particle pinebark, sphagnum peat moss and perlite or a commercial planting mixture containing those ingredients. The container is filled three-fourths inch from the top with dampened planting mixture. The seeds are planted from two to four times deep as they are wide and sprayed with fine mist of water. Whether they are grown indoors or outdoors, "Imagination" verbena seeds require covering so they are in the dark in order to germinate. The plant mix should drain well and not allowed become soggy. The seeds will take 21 to 28 days to germinate.